All-dielectric metasurfaces for circularly polarized beam-splitters with high conversion efficiency and broad bandwidth

Metasurface can arbitrarily control the polarization states of incident light and has attracted signicant attention. However, the transmission eciency of cross-polarization conversion of transmissive type metallic metasurfaces for polarized beam-splitters reported to date are low, especially the transmission eciency of cross-polarization conversion by single-layer metallic metasurfaces has a low theoretical upper limit of 25%, whose low value severely works against the application requirements. In this work, we propose two beam-splitters based on single-layer anomalous silicon metasurfaces, which can realize high conversion eciency and broad bandwidth wavefront control. A broadband half-wave plate and the high-eciency beam splitting of quarter-wave plate with circularly polarization beam are both achieved. Moreover, with big incident angles, the metasurface still maintains high-eciency performance.